The first version of YNAB WAS Excel. They found that it was too limiting and couldn't do everything people wanted. YNAB is so simple to use once you have it setup. I just import my transactions every week, and then go through and approve them. I'll reconcile the accounts to make sure everything is peachy. Then look at the budget page to see if i need to move any cash around.
My favorite part about YNAB that is harder to get with Excel is the ability to plan for longer term expenses. For instance, I know that I'm going to have a car insurance bill arriving any day now. My last bill was $840 6 months ago. If I didn't plan for that bill ahead of time, it could be very devastating to my finances depending on how tight I live. For me, cash flowing a large expense like $850 would be difficult, depending on how much on-call I had that month. Some months I'll easily have an extra 1k that I can send to savings. Others, I'm short $100 or so. It just depends on where the paychecks fall with my on-call. Luckily, I took the time to take all of those types of irregular bills and entered them in as YNAB categories. I then divide the total amount of the anticipated bill by the months I have to accrue the money. So for instance, $840/6 = $140 a month. I've been putting $140 a month into my insurance category, and when I get the bill in the next week or two, I'll just make the payment. I have categories for all kinds of things like that. Here are some examples:
Amazon Prime = $8.35
Amex Preferred Annual Fee = $6.25
Car Registration = $16
Car Insurance = $140
Crash Plan = $4
Fire Wood = $10
Garbage = $18
Propane = $3
Sams Club = $4
Medical Deductible = $21
Total each month = $230.60
Current balance on each of those "categories" is $2149.94. That's a lot of potential liability that I'm mitigating. I also have sinking funds for things like car repairs, gifting, home maintenance, vacation, etc. I like the idea of looking at cars as regular expenses instead of free till something breaks. I calculated what I think I'll spend in car repairs in a year. I then split it into 12 monthly payments. So when my car needs new brakes, I'll just buy them (and install them myself to make the money go further). I don't have to worry about where the money will come from.
The weakness with YNAB is that for the target audience of MMM, having a tight budget is not the problem. Most of us have a mountain of excess, and we just need to start saving it up. For me, I truly do have a lot of excess. But my problem is that I worry. I know that cars need repairs, roofs need replacing, and furnaces are going to crap out on you. It's all inevitable. I don't want to put money into my brokerage, just so that I can have to pull it out WHEN (not if) things break. YNAB lets me have my cake and eat some of it too. I can be confident that I'm planning on my big upcoming expenses, I keep my small expenses from creeping up, and I can feel free to put any excess money into my brokerage, knowing that the odds of me needing it are crazy small. What I will tell you is that my brokerage has been going up at a very steady pace over the last year. Without YNAB, I'd be lucky if my checking account kept even.